Weird....my dealer is telling me , i also researched, anything emissions related is warrantied for 8 yrs 80000 miles, dealership assured me i will not pay any out of pocket. I have the same code, car runs and starts fine, but fuel mileage sucks, this also flatlines my lfp logs, so i cannot log my lpfp. This error may keep lpfp operating at maximum, thus maybe affecting fuel mileage, but am scared.to dealer my car because i know my car will start all sorts of problems.after dealer gets ahold of my car lol...btw i have 08 e60, 30000 miles and 29f3 was there before my jb4 and before using e85...

So I took it to these local guys that run a small bmw shop. They walnut blasted it for me, and changed the plugs. They said the plugs looked fine. They took before and after pictures of the intake valves and port, wow what a difference. The walnut blast and spark plugs got rid of the misfire, the car runs fan freaking tastic now.

so the sequence of events I experienced was:
1. p29f3 LPFP sensor failure, along with misfire, replaced LPFP sensor, still misfiring - it was the same cylinder creating the check engine light when misfiring. I had no long cranks, but i began getting idle misfires. The longer it got cold outside the worse my car ran.

2. walnut blasted and plugs changed. Car runs like a top. plugs didn't look too bad, intake valves and ports were caked pretty bad - car is at 37000 miles at this point.

Wanted to say thanks for the info in this thread. I had the usual fuel pump code along with the low pressure sensor code 29F3 and am out of warranty. Cleared codes with INPA and 29F3 came right back. I tried to get INPA working to measure that sensor but no luck at all, going to keep working on that. I thought I would share some feedback on the replacement. In my opinion removing the cowl makes things easier and only takes a few additional minutes. I didn't remove it until I was putting things back together and made it easier to access that rear intake inlet but I was also installing a DCI. You don't need any special tools for the black box, just pull up and towards you from the drivers side. If necessary you can pry a small flat head into the clips to get it out but mine was no trouble. Also I left the wires on the sensor and just unclipped it from the black box, it was too hard to get to otherwise and didn't want to risk breaking it. Before putting things back together, it's a good time to clean the throttle body and oily chargepipe.

yea, take the intake and throttle body off, move the wiring harness and you are set. took me 30 minutes; the DCI and aftermarket charge pipe makes its easier.

the real question i have is how many people are having this issue, and better yet, how many people are having this issue shortly after using E85. I am now thinking E85 accelerated the aging of the sensor.

used e85 for about a week and bammmm there went the codes before that on 93 octane never had an issue.